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Age / Sex : /
Age / sex: 46/M
C.C.: Wrist pain after trauma (5 months ago)
1) What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of this case.
* Send Application Answers to Ja-Young Choi, MD (drchoi01@radiol.snu.ac.kr)
Courtesy : Ja-Young Choi, MD., Seoul National University Hospital
Diagnosis: 1st intersection SD
Discussion
Findings:
Axial T1-weighted image shows tendon anatomy at cross over junction. Fist extensor compartment tendons, abductor pollicis longus and extensor pollicis brevis tendons, cross superficial relative to second extensor compartment tendons, extensor carpi radialis longus/brevis tendons. Axial T2-weighted image reveals peritendinous edema in region of intersection of first extensor compartment and second extensor compartment tendons. Contrast-enhanced axial/coronal fat-suppressed T1-weighted image shows subcutaneous edema and enhancement predominantly in interval between first and second extensor compartment tendons.
Differential Diagnosis:
De Quervain tenosynovitis
Discussion:
Intersection syndrome is tenosynovitis of the radial wrist extensors, extensor carpi radialis longus (ECRL), and extensor carpi radialis brevis (ECRB). The condition also affects the extensor pollicis brevis (EPB) and the abductor pollicis longus (APL), causing pain and swelling of these muscle bellies. This is characterized by pain and swelling in the distal dorsoradial forearm. Intersection syndrome can be caused by direct trauma to the second extensor compartment. It is more commonly brought on by activities that require repetitive wrist flexion and extension. Weightlifters, rowers, and other athletes are particularly prone to this condition. While this condition occurs at the intersection of the first and second extensor compartments, many contend that the condition is a tenosynovitis of the ECRL and ECRB tendons. However, the condition has long been held to be caused by friction from the overlying EPB and APL tendons (Wood, 1973). MRI is well suited to show the findings of intersection syndrome, especially with fluid-sensitive sequences. The most important finding is the presence of peritendinous edema concentrically surrounding the second and the first extensor compartments, beginning at the point of crossover,4–8 cm proximal to the Lister tubercle and extending proximally. Peritendinitis may be a more appropriate broader term, given that there may not be tendon sheath fluid found in this location; interstitial fluid may surround the tendons and tendon sheaths or may be found in the interval between them at the intersection point. The implication is that intersection syndrome may have findings of an associated reactive tenosynovitis. Mild subcutaneous edema adjacent to the intersection point is also a feature, probably resulting from surrounding hyperemia. Findings of tendinosis (thickening and signal abnormality) may not be present, reflecting principally a peritendinous phenomenon. Mild tendon thickening and morphologic alterations are often subjective and raise a set of observer performance issues when trying to apply these findings consistently in practice. The treatment paradigm is similar to other overuse injuries. Conservative measures are the first line of treatment. Symptoms resolve within 2–3 weeks in 60% of patients with rest, administration of nonsteroid anti-inflammatory drugs, and splinting. Surgery is indicated typically only for patients not responding to therapy. When conservative treatment fails, a tenosynovectomy and a fasciotomy of abductor pollicis longus can be performed.
Reference
1. Cost CR, Morrison WB, Carrino JA. MRI features of intersection syndrome of the forearm. AJR 2003;181:1245-1248
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